1. Field of the Invention
The present invention relates to a semiconductor memory device. More particularly, the present invention relates to a NAND cell type of electrically erasable programmable read only memory (EEPROM) which is provided with a constant-current circuit having a current trimming function and suitable for use in a power supply circuit or the like.
2. Description of the Related Art
Conventionally, a NAND cell type of EEPROM is well known as a nonvolatile semiconductor memory device (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 10-275481). A voltage-to-current conversion circuit is usually used in the power supply circuit of a NAND cell type of EEPROM.
In recent years, attention has been paid to a constant-current circuit having a current trimming function as the voltage-to-current conversion circuit (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 11-346127). Application of such a constant-current circuit to the power supply circuit of a semiconductor memory device has also been examined.
Although application of a constant-current circuit having a current trimming function to the power supply circuit of a NAND cell type of EEPROM has also been considered, however, it has not yet been put to practical use.